The following relates generally to wireless communication, and more specifically to paging for machine type communication (MTC) devices.
Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power). Examples of such multiple-access systems include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, and orthogonal frequency division multiple access (OFDMA) systems. A wireless multiple-access communications system may include a number of base stations, each simultaneously supporting communication for multiple communication devices, which may each be referred to as a user equipment (UE).
In some cases, a base station may signal to a UE that paging and/or system information is available in a channel for one or more of the UEs by sending a paging message during a particular subframe, which may be referred to as a paging occasion, for those one or more UEs. Some systems have multiple subframes of a radio frame available for paging. A UE may monitor its particular paging occasion, in a particular subframe, to receive the paging message to determine that paging information and/or system information is available for the UE.
In some cases, a UE may be a low-cost or low-complexity MTC device (e.g., including an internet of things (IoT) device, machine to machine (M2M) communications device, etc.). Certain MTC devices may communicate with a base station in a narrow subband or narrowband regions of the system bandwidth of a wireless communications system. Such UEs may be referred to as narrowband devices. Because of the reduced bandwidth available for communications between a base station and narrowband device, certain signals provided by the base station may have reduced opportunities for transmission, which may impact certain UE operations. For paging operations, narrowband operation may reduce the number of subframes available for paging messages, effectively limiting the paging capacity and impacting system performance. In some instances, many of the subframes may be occupied with other data or control information, for example the subframes may be assigned to be multimedia broadcast single frequency network (MBSFN) subframes, or for synchronization signals, or some other predetermined purpose that limits subframes availability for paging. Limiting the number of subframes available for paging messages may increase the number of collisions between UEs monitoring the subframe for paging messages and/or reduce overall paging capacity.
In some circumstances, there may be many MTC devices (e.g., UEs) monitoring a limited number of paging occasions. A control channel carrying the paging message may be repeated a certain number of times to increase the probability of successful receipt of a paging message by one or more UEs intended to receive the paging message during a given paging occasion. However, in some cases the repeated paging message for a first UE intended to receive the paging message may overlap with paging occasions for other UEs that are not intended to be recipients of the paging message. If these other UEs successfully decode the paging message, they may determine that there is paging information available for them, when the paging information is actually for the first UE. Thus, the one or more UEs may stay awake longer than needed (e.g., beyond the time of the paging occasion to decode subsequently-received paging information) only to discover that the subsequently-received paging information is for a different UE. Remaining awake may use excessive power and drain battery life for the one or more UEs.